Fabrication and Photoelectrochemical Properties of [Ru(bpy)2dppz]2+ on ITO Electrode Associated with the Oxidation of Guanine

Electrochemical assembly of [Ru(bpy)(2)dppz](2+){bpy=2,2'-bipyridine, dppz=dipyrido[3,2-a:2',3'-c]phenazine} on an ITO electrode in the presence of guanine and photoelectrochemical properties of the assembled layer were investigated. It has been found that [Ru(bpy)(2)dppz](3+/2+) can be assembled onto the ITO electrode by the method of repetitive voltammetric sweeping, and the assembly is enhanced by guanine. The peak currents of prewaves increase linearly up to a guanine concentration of 0.25 mmol/L. More importantly, upon illumination with 470 nm light source and at an applied potential of 0.2 V, cathodic current for the fabricated layer on the ITO electrode indicate a linear enhancement with the rise of guanine concentration. Meanwhile, [Ru(bpy)(2)dppz](2+) can be served as an excellent mediator to prompt the oxidation of guanine, and the mediated peak current increases linearly with added guanine concentration from 0.01 to 0.25 mmol/L. In addition, the assembly mechanism of [Ru(bpy)(2)dppz](2+) on the ITO electrode associated with the oxidation of guanine and the assistance of light irradiation were discussed.